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A Metal‐Free Donor–Acceptor Covalent Organic Framework Photocatalyst for Visible‐Light‐Driven Reduction of CO 2 with H 2 O
Author(s) -
Lei Kai,
Wang Di,
Ye Liqun,
Kou Mingpu,
Deng Yu,
Ma Zhaoyu,
Wang Li,
Kong Yan
Publication year - 2020
Publication title -
chemsuschem
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 2.412
H-Index - 157
eISSN - 1864-564X
pISSN - 1864-5631
DOI - 10.1002/cssc.201903545
Subject(s) - photocatalysis , photochemistry , visible spectrum , covalent bond , covalent organic framework , triazine , chemistry , metal , stoichiometry , acceptor , molecule , materials science , inorganic chemistry , catalysis , polymer chemistry , organic chemistry , physics , optoelectronics , condensed matter physics
Visible‐light‐driven CO 2 reduction to valuable chemicals without sacrificial agents and cocatalysts remains challenging, especially for metal‐free photocatalytic systems. Herein, a novel donor–acceptor (D–A) covalent organic framework (CT‐COF) was constructed by the Schiff‐base reaction of carbazole‐triazine based D–A monomers and possessed a suitable energy band structure, strong visible‐light‐harvesting, and abundant nitrogen sites. CT‐COF as a metal‐free photocatalyst could reduce CO 2 with gaseous H 2 O to CO as the main carbonaceous product with approximately stoichiometric O 2 evolution under visible‐light irradiation and without cocatalyst. The CO evolution rate (102.7 μmol g −1 h −1 ) was 68.5 times that of g‐C 3 N 4 under the same conditions. In situ Fourier‐transform (FT)IR analysis indicated that CT‐COF could adsorb and activate the CO 2 and H 2 O molecules and that COOH* species may be a key intermediate. DFT calculations suggested that nitrogen atoms in the triazine rings may be photocatalytically active sites.